Interfractional body surface monitoring using daily cone-beam computed tomography imaging for pediatric adaptive proton therapy
Year: 2025
Type: article
Abstract: • A novel method detected tissue discrepancies per spot in the proton beam path. • The impact on plan quality was assessed based on water equivalent path length. • 5 mm change in body surface led to a drop in clinical target volume D min by 11.7 %. • A daily monitoring tool was proposed for adaptive proton therapy workflows. A novel method was developed to detect body surface changes on daily cone-beam computed tomography (CBCT) and estimate the impact on proton plan quality for pediatric patients. Simulation CT, daily CBCT, and repeat CT images were collected for 21 pediatric non-central nervous system (CNS) patients. Changes in the body surface in the proton beam path (ΔSurface CBCT ) were calculated for each spot by comparing simulation CT with daily CBCT. Subsequently, changes in water equivalent path length (WEPL) (ΔWEPL Synthetic CT ) were calculated for each spot by comparing the simulation CT with the synthetic CT converted from daily CBCT. The ground truth surface (ΔSurface Repeat CT ) and WEPL changes (ΔWEPL Repeat CT ) were calculated by comparing the simulation CT with the repeat CT taken on the same day as the CBCT. The root-mean-square (RMS) error between the ΔSurface CBCT and ΔSurface Repeat CT was 1.3 mm, while the RMS error between ΔWEPL Synthetic CT and ΔWEPL Repeat CT was 1.6 mm. A strong linear correlation was determined between ΔSurface CBCT and ΔWEPL Synthetic CT (R 2 = 0.97). The non-linear regression analysis of the dose volume parameters indicated that a 5 % decrease in clinical target volume (CTV) D min and D 99% was caused by 3.9 mm and 6.3 mm of ΔSurface CBCT , and 4.0 mm and 6.6 mm of ΔWEPL Synthetic CT , respectively. The findings revealed that a 5 mm change in body surface can lead to a significant degradation of plan quality, reducing CTV D min by 11.7 % and underscoring the need for adapting treatment plan.
Institution: St. Jude Children's Research Hospital
Language: English
Subfield: Radiation
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,980
OpenAlex ID: W4408187289